Throughout human history malaria has plagued mankind. Malaria remains the single most devastating parasitic infectious agent in the world, particularly in the developing and tropical world. Malaria infects hundreds of millions and kills roughly 2 million people each year. Globally the situation is worsening, largely due to the emergence of multidrug resistant strains of the responsible parasite.
In the past, the inexpensive, effective and orally available antimalarial drug, chloroquine, was the “gold standard” treatment. Unfortunately, certain Plasmodium sp. strains have evolved resistance to chloroquine. In fact, the spread of chloroquine-resistant Plasmodium sp. parasites has rendered chloroquine almost useless for malaria treatment. Multidrug resistant strains no longer susceptible to quinoline and anti-folate-based antimalarials are common in Southeast Asia and some parts of Africa. In addition, Plasmodium sp. resistance to other antimalarial drugs, such as artemisinin and its derivatives, has been reported. These are particularly devastating problems in many impoverished parts of the world where such drugs are most needed.
Multidrug resistance is a phenomenon which has been observed in cancer and in and other conditions, such as bacterial, viral, protozoal, and fungal diseases. Multidrug resistance is a particular problem in diseases such as malaria, tuberculosis, Entamoeba histolytica (amoebic dysentery), trypanosomiasis (African sleeping sickness), leishmaniasis and AIDS pneumonia, among others. A number of diverse drugs have been found effective against such diseases, but in multidrug resistance a disease becomes resistant to a variety of drugs to which it initially was susceptible. In many examples, multidrug resistance renders drugs that worked initially totally ineffective. Thus, there is a need not only for new antimalarial drugs, but also for new drugs to treat multidrug resistance.
Parasitic diseases have also been associated with psychotic diseases such as schizophrenia. In other words, parasitic infection in a subject could result in schizophrenia and schizophrenic symptoms. There exists a continued need for anti-psychotic drugs.